This invention relates to the field of dentistry, and more specifically to orthodontics syringe apparatus of the type having a handle at one end and having an intra-oral nozzle at the other end.
Hand-held syringes that control the flow of a liquid and/or air into a body cavity such as the oral cavity are known. Typically, such a syringe is an L-shaped device having a handle, a nozzle, and one or more finger-actuated valves that are spring-biased closed, and whose operation controls the outward flow of liquid and/or air from the nozzle, with the handle being connected to one or more flexible and under-pressure fluid/air supply hoses. Often these valves are the well known Schrader valves of the type used in pneumatic tire stems. In this way, fluid, air, or a mixture of fluid and air can be selectively discharged from the nozzle. The following United States patents are examples of known prior devices. These patents are incorporated herein by reference.
U.S. Pat. No. 5,045,055 provides a medical/dental syringe that includes an elongated handle having a nozzle connected to one thereof, and having a two-hose assembly connected to the other end thereof. The handle includes a valve body head, two flow-control valves, and two finger actuators for the flow-control valves, to thus selectively control the flow of water, air, or both water and air from the nozzle. The two flow-control valves, and their O-rings, are removable to facilitate periodic replacement. The use of VITON-brand O-rings is suggested in order to resist the effect of repeatedly subjecting the O-rings to high temperature. Automatic valves within the two-hose assembly operate to seal the water hose and the air hose when the two-hose assembly is disconnected from the handle.
U.S. Pat. No. 5,125,835 provides a retainer assembly for detachably mounting the multiple-conduit tip of a syringe onto a syringe head by way of a spring-biased locking collar. The tip includes an annular groove that receives a plurality of ball elements when the tip is inserted into the syringe head. A movable and spring-biased collar that is carried by the syringe head retains the ball elements within the tip""s groove, thus removably mounting the tip on the syringe head.
U.S. Pat. No. 5,199,871 provides a control valve for a dental syringe. The control valve, having a finger-actuator, is mechanically locked in a passageway that is provided within a syringe-head by the operation of an O-ring that expands into a groove that is provided in the wall of the passageway.
U.S. Pat. No. 5,234,338 provides an autoclavable head and handle for a dental syringe wherein the entire external housing, including the handle, can be removed from utility supply lines, so that the external surfaces of the housing can be autoclaved. This function is facilitated by providing a substantially internal quick-disconnect mechanism or cartridge whereby the flow of air and water to the syringe is discontinued, such that the syringe""s handle, head and tip can be steam-sterilized.
U.S. Pat. No. 5,848,893 provides that a syringe""s shutoff valves are mechanically retained in place within a syringe head by way of a retaining pin that seats within a groove that is contained within each of the shutoff valves, this retaining pin entering the groove when that valve""s inlet hose barb is screw-mounted onto the syringe head. In addition, the syringe nozzle is retained in an adapter that screw-mounts to the syringe head by way of a resilient snap-ring that encircles the nozzle and sits within a groove that is formed in the nozzle.
U.S. Pat. No. 6,293,792 is similar to above-mentioned ""835 patent wherein the ball-activated quick-tip-connect mechanism is constructed so as to also seat the balls of the quick-connect mechanism in radially-placed indentations that are carried by the tip. In this way the balls additionally provide structural interference against rotation of the tip.
The present invention provides a new and useful dental syringe that is constructed and arranged such that the internal portions of the syringe that contain O-rings, or at least the portion of the syringe that contains valve-associated O-rings, can be removed from the syringe prior to the syringe being sterilized, as by autoclaving. Thus, all O-rings that function within the syringe, or at least the O-rings that function within the syringe""s valves, are constructed of a material such as neoprene that would likely be damaged by autoclaving.
In order to provide an aesthetically pleasing and nicely weight-balanced syringe, the syringe of this invention includes (1) an internal and top-located insert, which could be made of metal, plastic, or any other suitable material, to contain flow-channels and the like that are required to accommodate air and/or water flow between the syringe""s two valves and the syringe""s nozzle, (2) a generally hollow and light-weight metal handle-body at whose upper end a nozzle and the insert are located, and (3) an internally-located and elongated light-weight, metal, and manually-removable valve body that extends internally the length of the handle body, so as to locate the syringe""s two valves at the upper end of the handle body and generally adjacent to and beneath the insert, and so as to locate two hose barbs at the bottom of the handle body.
This construction and arrangement wherein the syringe""s two normally-closed valves are placed at the top of a removable valve body whose bottom area contains two hose barbs to which water and air supply hoses are connected provides that when this valve body is manually removed or disconnected from the syringe, the syringe""s two normally-closed valves are removed with the valve body, and the two hoses are disconnected from the syringe, thus providing a removed valve body in which the two supply hoses are scaled by operation of the two normally-closed valves.
When assembling the syringe of the present invention, the syringe""s insert is first inserted into an upper portion of the handle body. An insert assembly pin is then inserted into an opening that is provided in an upper portion of the handle body. This insert assembly pin penetrates an opening in the insert, and thereby secures the insert within the handle body. Two side-by-side located, virtual-center-movable, and semi-circular valve actuating rods are carried by the insert, and this first assembly step places the top end of these two virtual-center valve actuating rods in positional cooperation with two O-ring-retained valve actuating buttons that are inserted into two side-by-side holes that are located on an upper inclined surface of the handle body.
As a second assembly step, the valve body is inserted into an opening that is located at the bottom of the handle assembly. This second assembly step places a normally-closed air valve and a normally-closed water valve that are located at the top of the handle member under the insert, and in positional cooperation with the bottom end of the two valve actuating rods. The two curved valve actuating rods enable the linear direction of movement of the two buttons to be inclined to the linear direction of movement of the two valves.
As a third assembly step, a lock pin is inserted into an opening that is provided in the upper portion of the handle assembly. This lock pin is adapted to enter an O-ring-containing groove that is provided in a spigot or post that is carried at the top of the valve body. As will be apparent from the following description, the lock pin and a release ring together lock the valve body in the handle body.
The syringe""s nozzle is connected to a manually rotatable release ring that encircles the outer diameter (OD) of the nozzle. The release ring is secured to the nozzle by way of a coiled torsion spring, one end of which is retained by the release ring. The coil of this torsion spring grips the outer diameter (OD) of the nozzle. That is, the inner diameter (ID) of the torsion spring is somewhat smaller than the OD of the nozzle. The release ring is secured to the body of the syringe by an assembly pin.
When assembling the release ring and the nozzle, one end of the torsion spring is retained by the release ring, and the torsion spring is then rotated against its wound direction, to thereby produce a spring ID that is larger than the nozzle OD. With the spring held in this larger ID state, the nozzle is now inserted into the center of the release ring, and the release ring is placed at a desired location along the length of the nozzle. The torsion spring is now released, whereupon the ID of the torsion spring decreases, thereby causing the release ring to be rotatably mounted at this desired position on the OD of the nozzle.
As a fourth assembly step, the release ring is secured to the body of the syringe with the assembly pin. The release ring presses against the lock pin and locks the valve body in the handle.
As the fifth and final assembly step, an end of the nozzle is inserted into the release ring by rotating the release ring thereby unwinding the torsion spring so as to facilitate inserting the nozzle within the release ring and torsion spring. The release ring and torsion spring can then be released thereby securing the nozzle to the release ring. Later, when it is desired to disconnect the valve body from the syringe, the above-mentioned release ring is rotated about 30 degrees around the nozzle. This rotation of the release ring coils the torsion spring, such that upon a subsequent release of the valve body, the release ring returns to its home position. This rotation of the release ring also brings a recessed portion of the release ring into positional coincidence with the above-mentioned lock pin. The above-mentioned O-ring that was compressed by the lock pin now operates to push the lock pin out of the above-mentioned groove in the spigot that is located at the top of the valve body, the valve body is no longer locked by the lock pin, and the valve body can now be pulled downward and out of the handle body. Note that since the top of the valve body carries normally closed valves, the supply hoses that are connected to the bottom of the valve body remain sealed.
As above described, syringes in accordance with this invention include two top-located and finger-operated buttons that, when pressed, selectively provide for the supply of pressurized air and/or water to the syringe""s nozzle. In accordance with the invention, a new and unusual virtual-center actuator rod extends between the bottom of these two buttons and the top of an associated valve, so as to translate a linear force that is applied to a button into a linear valve-opening force that is applied to an associated valve. These two virtual-center actuator rods are arranged such that the direction of linear movement of each button extends at an angle to the direction of linear movement of the associated valve.